Tissue fixation device

ABSTRACT

A suture anchor is formed of a material which absorbs body liquid when exposed to body liquid. The anchor may be at least partially formed of a material having a strong affinity for body liquids. This enables the anchor to absorb body liquid and expand upon being inserted into a patient&#39;s body. At least one embodiment of the suture anchor has portions formed of a relatively hard material which does not absorb body liquids and is pressed against body tissue by the material which absorbs body liquid to mechanically interlock the suture anchor and the body tissue. The anchor may be at least partially formed of a cellular material. The cells expand to absorb body liquid. At least one embodiment of the anchor has a pointed leading end portion to form an opening in an imperforate surface on body tissue. The configuration of the anchor may be changed by tensioning the suture while the anchor is disposed in body tissue.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/442,353filed May 21, 2003. The aforementioned '353 application is itself acontinuation of application Ser. No. 09/703,058 filed Oct. 31, 2000 (nowU.S. Pat. No. 6,572,635). The aforementioned '058 application is itselfa continuation of application Ser. No. 09/378,190 filed Aug. 20, 1999(now U.S. Pat. No. 6,152,949). The aforementioned '190 application isitself a continuation of application Ser. No. 08/964,167 filed Nov. 4,1997 (now U.S. Pat. No. 5,980,559). The aforementioned '167 applicationis itself a divisional of application Ser. No. 08/699,553 filed Aug. 19,1996 (now U.S. Pat. No. 5,718,717). The benefit of the earlier filingdates of the aforementioned applications is hereby claimed.

BACKGROUND OF THE INVENTION

The present invention relates to new and improved suture anchor and morespecifically to a suture anchor which is capable of expanding in apatient's body to enable the anchor to withstand relatively largepull-out forces.

Anchors are commonly utilized to retain sutures in a patient's body. Theanchors have previously been formed of metal, such as stainless steel ortitanium. In addition, anchors have been formed of biodegradablematerials. These known anchors have relied upon mechanical interlocksbetween the body tissue and the anchor to retain the anchor in placeagainst the influence of force transmitted through the suture to theanchor. It has previously been suggested to construct anchors in themanner disclosed in U.S. Pat. Nos. 5,405,359; 5,403,348; 5,203,787;5,046,513; and 5,041,129. In addition, an anchor formed of body tissueis disclosed in co-pending application Ser. No. 08/626,393 filed Mar.29, 1996 filed by Peter M. Bonutti and entitled “Suture Anchor”.

SUMMARY OF THE INVENTION

The present invention relates to a new and improved suture anchor whichabsorbs body liquid. A suture extends from the anchor. The anchor andthe suture are inserted into a patient's body. When the anchor isdisposed in the patient's body, the anchor expands. The anchor expandsby absorbing body liquid and/or by its own natural resilience. As theanchor expands, an improved interlock is obtained between the anchor andthe body tissue to enable the anchor to resist relatively large tensionforces transmitted through the suture.

The anchor may be formed of a material which absorbs body liquid.Alternatively, the anchor may contain cells which are expanded to absorbbody liquid.

The anchor may have a leading end portion which forms an opening in animperforate body surface. Alternatively, the anchor may be inserted intobody tissue through an opening formed in the body tissue by a memberother than the anchor. The configuration of the anchor may be changedwhile the anchor is in the body tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the invention will become moreapparent upon a consideration of the following description taken inconnection with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration depicting the manner in which ananchor is inserted into a patient's body with a suture extending intothe anchor;

FIG. 2 is a schematic illustration depicting the manner in which theanchor of FIG. 1 is pivoted in the patient's body;

FIG. 3 is a schematic illustration depicting the manner in which thepatient's body tissue is secured with the anchor immediately after theanchor has been inserted into the patient's body;

FIG. 4 is a schematic illustration, generally similar to FIG. 3,illustrating the manner in which the anchor expands by absorbing bodyliquid after the anchor has been inserted into the patient's body;

FIG. 5 is a schematic illustration depicting another manner in which theanchor of FIG. 1 may be inserted into a patient's body;

FIG. 6 is a schematic illustration depicting the manner in which theanchor of FIG. 5 expands in the patient's body by absorbing body liquid;

FIG. 7 is a schematic illustration, generally similar to FIG. 1,illustrating the manner in which a second embodiment of the anchor maybe inserted into a patient's body through an imperforate surface on bodytissue;

FIG. 8 is a schematic pictorial illustration of a third embodiment ofthe anchor having a portion which absorbs body liquid and a portionwhich does not absorb body liquid and has projections to engage bodytissue;

FIG. 9 is a schematic pictorial illustration of a fourth embodiment ofthe anchor having a core which absorbs body liquid and a casing formedof an elastic material which does not absorb body liquid;

FIG. 10 is a pictorial schematic illustration of a suture receivingopening formed in material which does not absorb body liquid and isconnected with a main portion which absorbs body liquid;

FIG. 11 is a schematic illustration of a an apparatus for inserting ananchor having cells which are collapsed before the anchor is moved intoa patient's body;

FIG. 12 is a schematic illustration of another apparatus for insertingthe anchor of FIG. 11 into body tissue;

FIG. 13 is a schematic illustration of the manner in which theconfiguration of an anchor is changed while the anchor is in thepatient's body tissue; and

FIG. 14 is a schematic illustration of another manner in which theconfiguration of an anchor is changed while the anchor is in a patient'sbody tissue.

DESCRIPTION OF SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION

General Description

Suture anchors have previously been utilized to retain sutures in eitherhard or soft tissue in a human patient's body. The suture anchors havepreviously been formed of metal, biodegradable materials, and othermaterials. These known suture anchors have been retained in thepatient's body by changing the orientation of the anchor relative to thepatient's body once it has been inserted into the patient's body.Alternatively, known anchors have been retained in the patient's body bya mechanical interlock formed with the material of the patient's body bybarbs or other projections.

In accordance with one of the features of the present invention, suturesmay be retained in a patient's body by anchors which are at leastpartially formed of material which absorbs body liquid when exposed tothe body liquid. The material expands as it absorbs the liquid in thepatient's body. As the anchor expands, an improved interlock is formedbetween the anchor and body tissue of the patient's body. The improvedinterlock enables relatively large forces to be transmitted through asuture to the anchor.

In accordance with another of the features of the present invention,sutures may be retained in a patient's body by anchors which are formedof material which expands under the influence of its own naturalresilience. As the material expands, cells are expanded from a collapsedcondition. As the cells expand, the anchor absorbs body liquid by atleast partially filling the cells with body liquid. As the anchorexpands, an improved interlock is formed between the anchor and tissueof the patient's body. If desired, the material which forms the cellscould also absorb body liquid.

In accordance with another feature of the invention, the anchor could beinserted into a patient's body through an imperforate surface on bodytissue. This may be done by forming an opening in the body tissue with aleading end portion of the anchor. Alternatively, the opening could beformed by one or more members other than the anchor. Once the anchor hasentered the patient's body the configuration of the anchor may bechanged under the combined influence of force transmitted to the anchorthrough the suture and force applied against the outer surface of theanchor by body tissue.

Suture Anchor Formed of Material which Absorbs Body Liquid

A suture anchor 20 (FIG. 1) is formed of a material which absorbs bodyliquid when the anchor is exposed to body liquid. As the material of theanchor 20 absorbs body liquid, the anchor expands from the initialvolume of FIGS. 1-3 to the expanded volume of FIG. 4. As the material ofthe anchor 20 absorbs body liquid and expands, the volume of the anchorincreases and an improved mechanical interlock is formed between theanchor and body tissue in which the anchor has been inserted. Theimproved interlock enables the anchor 20 to resist large tension forcesin a suture 32 without pulling out of body tissue 22.

It is contemplated that the anchor 20 could be completely formed ofmaterial which absorbs body liquid. Alternatively, the anchor could bepartially formed of material which absorbs body liquid and partiallyformed of material which does not absorb body liquid. The material whichdoes not absorb body liquid may be provided with projections which areforced into the body upon expansion of the material which absorbs bodyliquid. This would result in at least two different interlocks beingobtained between the anchor and the body tissue, that is, an interlockdue to expansion of the material which absorbs body liquid and aninterlock due to engagement of projections on the material which doesnot absorb body liquid with the body tissue.

The suture anchor 20 is entirely formed of material which absorbs bodyliquid. In one specific instance, the suture anchor 20 was formed of apolymeric material which absorbs body liquid. The polymeric material maybe either a copolymer or a dipolymer. The polymeric material may behydrophilic. The polymeric material may be cellulose, petroylglutamicacid, high purity carboxymethylcellulose, a collagen, or polylactide. Itis believed that a ceramic as found in hydroxyapatite composites withpolyethylene, polylactide or polyhydroxybutyrate may be utilized to formthe anchor 20. Of course, the suture anchor 20 could be formed of otherknown materials which absorb body liquid.

It is theorized that the hydrophilic material forming the anchor 20attracts body liquid under the influence of molecular attraction andestablishes molecular linkages with the body liquid. The materialforming the anchor 20 is body liquid permeable. The body liquid entersminute cavities in the porous material forming the anchor 20 under theinfluence of capillary action. The attractive forces between moleculesof the body liquid and molecules of the material forming the anchor 20holds the body liquid in the minute cavities in the material forming theanchor.

In the embodiment of the invention illustrated in FIGS. 1-3, the sutureanchor 20 has a tubular cylindrical configuration. The suture anchor 20has a tubular wall 24 formed of material which absorbs body liquid. Thetubular wall 24 has a cylindrical outer side surface 26 which is coaxialwith a cylindrical inner side surface 28. The cylindrical inner sidesurface 28 forms a cylindrical passage 30 which extends axially throughthe center of the suture anchor 20.

The wall 24 of the suture anchor 20 is formed as one piece of a poroushydrophilic polymer which absorbs body liquid. Although it is preferredto form the anchor 20 with a cylindrical configuration, the anchor maybe shaped or ground to any one of many different axially tapering orflaring configurations, such as those disclosed in U.S. Pat. No.5,403,348. It is believed that it may be preferred to form the anchor 20with either a cylindrical configuration or a polygonal configuration.

Although it is contemplated that the tubular cylindrical suture anchor20 could be of many different sizes, it is believed that the sutureanchor may preferably have a length or axial extent of between 2 and 4millimeters. The cylindrical outer side surface 26 of the suture anchor20 may have a diameter of between 1 and 2 millimeters. The cylindricalinner side surface 28 of the passage 30 in the anchor 20 may have adiameter of 1 to 1 millimeter. Of course, the suture anchor 20 could beformed with many different dimensions and/or shapes if desired.

A suture 32 is inserted into the passage 30 in the suture anchor 20. Thesuture 32 includes a portion or leg 34 which extends away from a flatannular trailing end surface 36 of the anchor 20. In addition, thesuture 32 has a second portion or leg 38 which extends across a flatannular leading end surface 40 of the anchor 20. The leg 38 of thesuture 32 extends along the cylindrical outer side surface 26 of theanchor 20 to a location adjacent to and spaced from the leg portion 34of the suture 32. A relatively short portion 44 of the suture 32interconnects the leg portions 34 and 38 and is disposed in the passage30 in the suture anchor 20.

An inserter assembly 60 is used to position the suture anchor 20 and aportion of the suture 32 in a patient's body tissue 22. The inserterassembly 60 includes a cylindrical tubular outer sleeve 66 having acylindrical central passage 68 in which the anchor 20 is disposed. Theinserter 60 also includes a cylindrical tubular inner sleeve 72 which istelescopically received in the outer sleeve 66. The tubular inner sleeve72 has a conical tapered leading end portion 74 which engages an annulartrailing end surface 36 of the anchor 20.

The leg or portion 34 of the suture 32 extends through a cylindricalpassage 76 in the inner sleeve 72. The leg or portion 38 of the suture32 extends through the central passage 68 in the outer sleeve 66 along apath which extends between the inner and outer sleeves. The leg orportion 38 of the suture 32 could extend along the outside of the outersleeve 66. If desired, one of the legs or portions 34 or 38 of thesuture could be omitted. If this was done, the suture 32 could be tiedor otherwise secured to the anchor 20.

It is contemplated that the anchor 20 may be inserted into a humanpatient's body at many different locations. The anchor 20 may beinserted into either hard or soft tissue. In the situation illustratedschematically in FIG. 1, the anchor 20 is being inserted into bonetissue 22 in a patient's body. A cylindrical recess 80 is formed in thebone tissue 22 of the patient's body by drilling or other methods. Therecess 80 extends through a hard compact outer layer 82 of the patient'sbone tissue 22 into the relatively porous inner or cancellous tissue 84.

To insert the anchor 20 in the patient's body tissue 22, the cylindricalinner sleeve 72 is moved axially downward (as viewed in FIG. 1) to applyforce against a relatively small area on the annular trailing endsurface 36 of the anchor 20. Once the anchor 20 has been pushed into therecess 80 by axial movement of the inner sleeve 72 relative to the outersleeve 66, the leg 38 of the suture 32 is tensioned to apply forceagainst an annular leading end surface 40 of the anchor 20. At the sametime, the bevelled leading end 74 of the inner sleeve 72 is pressedagainst the trailing end surface 36 of the anchor.

This results in the application of a counterclockwise (as viewed inFIGS. 1 and 2) torque to the anchor 20. This torque causes the anchor 20to pivot through the orientation shown in FIG. 2 to the orientationshown in FIG. 3. Once the anchor 20 has been pivoted to the orientationshown in FIG. 3, by tensioning the suture 32 and applying force againstthe anchor with the leading end portion 74 of the inner sleeve 72, theanchor 20 engages the hard compact outer layer 82 of the patient's bonetissue to hold the anchor in the recess 80. Thus, a solid initialinterlock is obtained between the anchor 20 and body tissue 22.

The suture 32 is then tensioned to secure a member, such as body tissue90, in place. The member or body tissue 90 may be soft tissue, or aligament, or a tendon, or other body tissue. If desired, the suture 32may be used to secure other members, such as an implant or splint, inplace relative to the patient's body tissue 22. The suture is tensionedto transmit force between the anchor 20 and a member to be held inplace.

One specific known inserter assembly 60 and method of inserting a sutureanchor 20 into a patient's body tissue has been illustrated in FIGS.1-3. This specific inserter assembly and the method of inserting theanchor 20 are the same as is disclosed in U.S. Pat. No. 5,403,348 issuedApr. 4, 1995 and entitled “Suture Anchor”. However, it is contemplatedthat many different known types of inserter assemblies could be utilizedto install the suture anchor 20 with many different methods in apatient's body tissue. For example, the inserter assembly and methoddisclosed in U.S. Pat. No. 5,464,426 issued Nov. 7, 1995 and entitled“Method of Closing Discontinuity in Tissue” could be utilized ifdesired. Of course, other known apparatus and methods could also beutilized if desired.

In accordance with a feature of the invention, the suture anchor 20absorbs body liquid and expands once the suture anchor has been insertedinto the body tissue 22. The expansion of the suture anchor 20 improvesthe initial interlock between the anchor and body tissue 22. The initialinterlock between the anchor 20 and body tissue 22 is obtained bypivoting the anchor in the body tissue to the orientation shown in FIG.3. The improved interlock is obtained by expanding the anchor 20, asshown in FIG. 4. The improved interlock allows relatively large tensionforces to be transmitted through the suture 32 between the anchor 20 anda member to be held in place by the suture.

The suture anchor 20 expands in all directions, from the initial sizeillustrated in FIG. 3 to a relatively large expanded size illustrated inFIG. 4, shortly after the suture anchor has been inserted into the bodytissue 22. After the suture anchor 20 has been inserted into the bodytissue 22, the suture anchor is exposed to body liquids, indicatedschematically at 98 in FIG. 4. The body liquids 98 are drawn into thesuture anchor 20 due to the affinity of the polymeric material formingthe suture anchor 20 for body liquids.

As the body liquids 98 are drawn into the suture anchor 20, the anchorexpands in a substantially uniform manner in all directions. Thus, theanchor 20 swells both radially and axially. Substantially uniformexpansion of the entire outer side surface area of the suture anchor 20occurs as body liquids 98 are absorbed by the anchor. The extent ofexpansion of the suture anchor 20 will depend upon the specificcharacteristics of the material from which the suture anchor is formedand may vary between 10 and 50 percent by volume. Of course, the extentof expansion of the anchor 20 will be a function of the force appliedagainst the outer side surface of the anchor by the body tissue 22.

As the suture anchor 20 swells, the size of the anchor 20 increases. Asthe size of the anchor 20 increases, the outer side surface of theanchor presses both axially and radially outward against the body tissue22. As the anchor 20 expands and presses against the body tissue, thebody tissue is displaced by the anchor. Thus, the outer side surface ofthe anchor 20 applies force against the body tissue 22 and moves thebody tissue to make room for the anchor as the anchor expands. If theanchor 20 encounters a localized area of high resistance to expansion inthe body tissue, the anchor will expand around the localized area andmay even shift in the body tissue 22.

The expansion of the anchor 20 as it absorbs the body liquids 98 resultsin an increasing mechanical interlocking action between the anchor 20and the body tissue 22. There is an initial mechanical interlock betweenthe anchor 20 and the body tissue 22 when the anchor has its original orinitial size (FIG. 3). As body liquids 98 are absorbed by the sutureanchor 20 and the volume of the anchor increases, the anchor expands toimprove the mechanical interlock between the anchor and the body tissue22. The improved interlock between the anchor 20 and body tissue 22allows relatively large tension forces to be transmitted through thesuture 32 without pulling the anchor out of the body tissue.

Installation—Second Procedure

In the embodiment of the invention illustrated in FIGS. 1-4, the anchor20 was pivoted from the orientation shown in FIG. 1 through theorientation shown in FIG. 2 to the orientation shown in FIG. 3 to obtainan initial mechanical interlock between the anchor and body tissue 22.In the embodiment of the invention illustrated in FIGS. 5 and 6, theanchor is not pivoted from its initial orientation to obtain an initialmechanical interlock. The anchor is merely positioned in the body tissueand expanded in all directions by absorbing body liquid. The expansionof the anchor results in the formation of an interlock between theanchor and the body tissue. Since the embodiment of the inventionillustrated in FIGS. 5 and 6 is generally similar to the embodiment ofthe invention illustrated in FIGS. 1-4, similar numerals will beutilized to designate similar components, the suffix letter “a” beingassociated with the numerals of FIGS. 5 and 6 in order to avoidconfusion.

The suture anchor 20 a has the same construction and is formed of thesame hydrophilic polymeric material as the suture anchor 20 of FIGS.1-3. The suture anchor 20 a (FIG. 5) has a cylindrical tubularconfiguration. The suture anchor 20 a has a cylindrical outer sidesurface 26 a. A cylindrical central passage 30 a extends through thesuture anchor 20 a between opposite annular end surfaces 36 a and 40 aof the suture anchor 20 a.

A suture 32 a has a leg 34 a which extends through a passage 76 a formedin an inner sleeve 72 a; A second leg 38 a of the suture 32 a extendsthrough a central passage 68 a and a tubular outer sleeve 66 a. The leg38 a of the suture 32 a extends between a cylindrical inner side surface68 a of the inner sleeve 72 a and a cylindrical inner side surface ofthe outer sleeve 66 a.

It is contemplated that the anchor 20 a may be inserted into a patient'sbody at many different locations. The anchor 20 a may be inserted intoeither hard or soft tissue. In the situation illustrated schematicallyin FIG. 5, the anchor is being inserted into bone tissue 22 a in apatient's body with the inserter assembly 60 a. A recess 80 a is formedin the bone tissue 20 a of the human patient's body by drilling or othermethods. The cylindrical recess 80 a extends through the hard compactouter layer 82 a of the patient's bone tissue 20 a into the relativelyporous inner or cancellous tissue 84 a.

To insert the anchor 20 a in the patient's body tissue 22 a, the innersleeve 72 a is moved axially downward (as viewed in FIG. 5) to applyforce against the trailing end surface 36 a of the anchor 20 a. In thisembodiment of the inserter assembly 60 a, the inner sleeve 72 a has acylindrical leading end portion 74 a which applies a substantiallyuniform force over substantially the entire flat annular trailing endsurface 36 a of the anchor 20 a. Therefore, the anchor 20 a is notpivoted but is merely moved straight into the recess 80 a.

Once the anchor 20 a has been positioned in the recess 80 a, the anchorabsorbs body liquid 98 a and increases in volume as the liquid isabsorbed. This results in the anchor expanding in all directions fromthe initial size of FIG. 5 to a relatively large expanded sizeillustrated in FIG. 6. As the anchor 20 a expands, its size increases by10 to 50 percent by volume.

The anchor 20 a is porous and is formed of a hydrophilic material. Thebody liquid 98 a is drawn into openings in the porous material of theanchor 20 a by the affinity of the porous material forming the anchorfor the body liquid. The attractive forces between the material formingthe anchor 20 a and the body liquid holds the body liquid in the anchor.

As the anchor 20 a expands from the initial size, the outer surfaces onthe anchor press radially and axially against the body tissue 22 a.Substantially uniform expansion of the anchor 20 a forms a securemechanical interlock with the body tissue. This interlock enablestension forces to be transmitted through the suture 32 a between theanchor 20 a and a member, such as the body tissue 90 a.

As the anchor 20 a expands radially outward, the cancellous tissue 84 ais compressed and the size of the portion of the recess 80 a in thecancellous tissue 84 a is increased. As this happens, the diameter ofthe cylindrical anchor 20 a increases from a diameter which is justslightly less than the size of the portion of the recess 80 a whichextends through the hard compact outer layer 82 a of the bone tissue 22a to a diameter which is greater than the diameter of the portion of therecess 80 a extending through the hard compact outer layer 82 a of bonetissue. This results in the anchor 20 a being locked in place in thebody tissue 22 a.

The suture 32 a can then be used to secure a member 90 a in place in themanner illustrated schematically in FIG. 6. The member 90 a may be softbody tissue, or a ligament, or a tendon, or other body tissue. Ifdesired, the suture 32 a may be used to secure an implant or splint inplace relative to the patient's body 22 a. The interlock between theanchor 20 a and body tissue 22 a enables substantial tension force to betransmitted through the suture 32 a without pulling the anchor out ofthe body tissue.

The expansion of the anchor 20 a has been schematically illustrated inFIG. 6 as being uniform in all directions. This will be the case whenthe body tissue 22 a applies uniform forces against all sides of theanchor 20 a. However, the body tissue 22 a may provide nonuniformresistance to expansion of the anchor 20 a. When this occurs, the anchor20 a may shift in the body tissue 22 a under the influence of forcesapplied against the body tissue as the anchor expands. In addition oralternatively, the anchor 20 a may expand in a nonuniform manner.

Anchor—Second Embodiment

In the embodiment of the invention illustrated in FIGS. 1-4, the anchor20 has a generally cylindrical configuration and is formed entirely of ahydrophilic polymeric material which absorbs body liquid. The anchorillustrated in FIGS. 1-4, due to its relatively blunt leading endportion, is particularly well adapted for positioning in preformedrecesses in body tissue. In the embodiment of the anchor illustrated inFIG. 7, the anchor has a sharp or pointed leading end portion tofacilitate forming an opening in imperforate body tissue. Since theembodiment of the invention illustrated in FIG. 7 is generally similarto the embodiment of the invention illustrated in FIGS. 1-4, similarnumerals will be utilized to designate similar components, the suffixletter “b” being associated with the numerals of FIG. 7 to avoidconfusion.

The tubular cylindrical suture anchor 20 b has a generally cylindricalouter side surface 26 b which is coaxial with a cylindrical inner sidesurface 28 b. The cylindrical inner side surface 28 b forms a portion ofa passage 30 b which extends through the anchor 20 b. In addition to themain portion of the passage 30 b formed by the cylindrical side surface28 b, a second cylindrical side surface 110 has a central axis whichextends perpendicular to the central axis of the cylindrical sidesurface 28 b. The cylindrical side surface 110 intersects thecylindrical side surface 28 b and extends radially outward from thecylindrical side surface 28 b. The cylindrical side surfaces 28 b and110 cooperate to form the passage 30 b with a generally L-shapedconfiguration.

A suture 32 b is inserted into the passage 30 b in the suture anchor 20b. The suture 32 b includes a portion or leg 34 b which extends awayfrom a flat annular trailing end surface 36 b of the anchor 20 b. Inaddition, the suture 32 b has a second portion or leg 38 b which extendsalong the cylindrical outer side surface 26 b of the anchor 20 b andalong the cylindrical inner side surface 68 b of the outer sleeve 66 b.A relatively short portion 44 b of the suture 32 b interconnects the legportions 34 b and 38 b and is disposed in the passage 30 b in the sutureanchor 20 b.

An inserter assembly 60 b is used to position the suture anchor 20 b anda portion of the suture 32 b in a patient's body tissue 22 b. Theinserter assembly 60 b includes a generally cylindrical tubular outersleeve 66 b having a central passage 68 b in which the anchor 20 b isdisposed. The inserter 60 b also includes a tubular inner sleeve 72 bwhich is telescopically received in the outer sleeve 66 b. The tubularinner sleeve 72 b has a conical tapered leading end portion 74 b whichengages the trailing end surface 36 b of the anchor 20 b.

In accordance with a feature of the embodiment of the inventionillustrated in FIG. 7, the anchor 20 b has a leading end portion 112with a generally conical configuration. The leading end portion 112 ofthe anchor 20 b is adapted to form an opening in an imperforate outerside surface 114 of the patient's body tissue 22 b. In addition, theleading end portion 112 of the anchor 20 b facilitates moving the anchorinto the body tissue 22 b under the influence of force applied againstthe trailing end surface 36 b of the anchor 20 b by the tubular innersleeve 72 b. The conical leading end portion 112 of the anchor 20 b isformed by a conical layer of a relatively hard polymeric material. Thepolymeric material forming the leading end portion 112 may bebiodegradable if desired.

In addition, the anchor 20 b has a cylindrical body portion or wall 116which is disposed in a coaxial relationship with the leading end portion112. The cylindrical body portion 116 is formed of a hydrophilicpolymeric material which absorbs body liquid when exposed to the bodyliquid. The cylindrical body portion 116 is formed of the same materialas the anchor 20 of FIGS. 1-4. As the body portion 116 of the anchor 20b absorbs body liquid, the body portion of the anchor expands radiallyand axially to interlock with the body tissue 22 b. The leading endportion 112 is formed of a rigid polymeric material which does notabsorb body liquid.

The leading end portion 74 b of the tubular inner sleeve 72 b is taperedso that it applies force against the trailing end surface 36 b of theanchor 20 b at a relatively small area on the trailing end surface. Theconcentrated application of force to the trailing end surface 36 b ofthe anchor 20 b facilitates pivoting movement of the anchor in the bodytissue 22 b upon tensioning of the leg 38 b of the suture 32 b.

Assuming the anchor 20 b is to be moved into body tissue 22 b disposedbeneath a layer 120 of skin, force is applied against the tubular innersleeve 72 b to force the pointed leading end portion 112 of the anchoragainst the imperforate outer side surface 114 of the skin 120. Thisforce causes the anchor 20 b to pierce the skin 120 and enter soft bodytissue 122 disposed beneath the skin. Once the anchor 20 b has beenmoved completely beneath the skin 120 into the soft body tissue 122, theleg 38 b of the suture 32 b is tensioned. This results in theapplication of torque to the anchor 20 b tending to rotate or pivot theanchor in a counterclockwise direction from the orientation shown inFIG. 7 to a generally horizontal orientation, corresponding to theorientation of the anchor illustrated in FIG. 3. At this time, thelongitudinal central axis of the anchor will be generally parallel tothe skin 120.

Once the anchor 20 b has been moved into the body tissue 122 and pivotedin the manner previously explained, the body portion 116 of the anchorwill absorb body liquid such as blood or other fluids. As thehydrophilic body portion 116 of the anchor 20 b absorbs body liquids,the body portion expands in all directions and presses against the bodytissue 122. As the anchor expands, body tissue is displaced and themechanical interlock with the anchor 20 b is enhanced.

Thus, the anchor 20 b is mechanically interlocked with the body tissue122 by both pivotal movement of the anchor to a sidewise orientation andexpansion of the anchor as it absorbs body liquids. The improvedinterlock obtained by expanding the anchor 20 b enables relatively largetension forces to be transmitted between a member (not shown) and theanchor 20 b through the suture 32 b.

Anchor—Third Embodiment

In the embodiment of the anchor illustrated in FIGS. 1-4, the anchor isformed entirely of material which absorbs body liquid when it is exposedto the body liquid. In the embodiment of the anchor illustrated in FIG.8, a portion of the anchor is formed of material which absorbs bodyliquid and another portion of the anchor is formed of material whichdoes not absorb body liquid. The material which does not absorb bodyliquid has projections which engage body tissue to enhance an interlockbetween the anchor and the body tissue. Since the embodiment of theinvention illustrated in FIG. 8 is generally similar to the embodimentof the invention illustrated in FIGS. 1-4, similar numerals will beutilized to designate similar components, the suffix letter “c” beingassociated with the numerals of FIG. 8 in order to avoid confusion.

An anchor 20 c (FIG. 8) has a tubular cylindrical configuration. Asuture (not shown) extends through a central passage 30 c in the anchor20 c in the same manner as illustrated in FIG. 1 for the anchor 20.

In accordance with a feature of this embodiment of the invention, theanchor 20 c (FIG. 8) has a body portion 116 c which is formed of ahydrophilic polymeric material which absorbs body liquid when exposed tothe body liquid. In addition, the anchor 20 c includes a plurality ofidentical retaining portions 130, 132 and 134. The retaining portions130, 132 and 134 are formed of a relatively hard polymeric materialwhich does not absorb body liquid. The retaining portions 130, 132 and134 may be biodegradable if desired.

In the illustrated embodiment of the invention, the retaining portions130, 132 and 134 and a plurality of ribs or projections 138 which extendoutward from the retaining portion. When the anchor 20 c is positionedin body tissue in the manner previously explained in conjunction withthe embodiments of the invention illustrated in FIGS. 1-4, the bodyportion 116 c absorbs body liquid. When this occurs, the body portion116 c of the anchor 20 c expands radially and axially outward to enhancethe mechanical interlock with the body tissue.

As the body portion 116 c of the anchor 20 c expands, the retainingportions 130, 132 and 134 are moved radially outward away from thecentral axis of the anchor 20 c. This presses the ribs 138 on theretaining portions 130, 132 and 134 into the body tissue to furtherenhance the mechanical interlock between the anchor and the body tissue.Although the ribs 138 have been shown in FIG. 8 as having a generallyarcuate configuration and a generally smooth outer side surface, it iscontemplated that the ribs could have barbs or other projections whichwould impale the body tissue as the body portion 116 c of the anchor 20c absorbs body liquid and expands. Of course, this would further enhancethe mechanical interlock between the anchor 20 c and the body tissue.

In the embodiment of the anchor 20 c illustrated in FIG. 8, the anchorhas a generally flat annular leading end portion. However, it iscontemplated that the anchor 20 c could be provided with a conicalleading end portion, similar to the conical leading end portion 112 onthe anchor 20 b of FIG. 7. If the anchor 20 c were to be provided with aconical leading end portion, it is contemplated that the retainingportions 130, 132 and 134 could be extended in an axial direction toform the conical leading end portion as three separate segments. As thebody portion 116 c of the anchor 20 c absorbs body liquid and expands,the retaining portions 130, 132 and 134 would move radially outward awayfrom each other and the leading end portion of the anchor would expand.

A relatively strong interlock is obtained between the anchor 20 c andbody tissue. This interlock is obtained by changing the orientation ofthe anchor 20 c relative to the body tissue, in the manner illustratedfor the anchor 20 in FIG. 2. In addition, the interlock is obtained byexpansion of the anchor 20 c as the body portion 116 c absorbs bodyliquid. The interlock is also obtained by engagement of the ribs 138with body tissue. The result is a strong interlock which enables theanchor 20 c to resist very large tension forces transmitted to theanchor through a suture.

Anchor—Fourth Embodiment

In the embodiment of the anchor 20 illustrated in FIGS. 1-4, the anchoris formed entirely of material which expands when it is exposed to bodyliquid. In the embodiment of the invention illustrated in FIG. 9, theanchor is formed by a core of material which expands upon being exposedto body liquid and an elastic jacket which encloses the core. Since theembodiment of the invention illustrated in FIG. 9 is generally similarto the embodiment of the invention illustrated in FIGS. 1-4, similarnumerals will be utilized to designate similar components, the suffixletter “d” being associated with the numerals of FIG. 9 in order toavoid confusion.

An anchor 20 d (FIG. 9) has a cylindrical configuration. The anchor 20 dincludes a cylindrical core 144 which is enclosed by a tubularcylindrical jacket 146. A passage 30 d extends through both the core 144and the jacket 146. The passage 30 d extends diametrically through thecore 144 and the jacket 146 and has a cylindrical configuration. Asuture (not shown) is positioned in the passage 30 d. The suture may betied off at one end of the passage or may extend through the passage sothat legs of the suture extend along opposite sides of the jacket 146.

The jacket 146 is provided with a plurality of circular openings 150which extend through the jacket. The openings 150 enable body liquid topass through the jacket into the core 144. The jacket 146 is formed ofan elastic polymeric material which is easily stretched. The core 144 isformed of a material which absorbs body liquid upon being exposed to thebody liquid. In one specific embodiment of the suture anchor 20 d, thecore 144 was formed of a hydrophilic polymeric material which is thesame as the material forming the anchor 20 of FIGS. 1-4.

When the anchor 20 d is inserted into body tissue, in the mannerillustrated schematically in either FIGS. 1-3 or 5 and 6, the entireanchor 20 d is exposed to body liquid. The body liquid passes throughthe openings 150 and is absorbed by the core 144. As the core 144absorbs body liquid, the core expands and stretches the jacket 146.

Although the anchor 20 d has been shown as having a generallycylindrical configuration with flat annular end surfaces, it iscontemplated that the anchor could be provided with a conical leadingend portion, similar to the conical leading end portion 112 of theanchor 20 b of FIG. 7. The conical leading end portion could be formedeither as a portion of the jacket 46 or separately from the jacket. Itis believed that it may be preferred to form a conical leading endportion for the anchor 20 d separately from the jacket 146 to enable theleading end portion to be formed of a hard material which is not readilystretched and which is capable of piercing an imperforate surface ofbody tissue.

In the illustrated embodiment of the invention, the jacket 146 is formedof a material which is resiliently stretched when the core 144 absorbsbody liquid and expands. It is contemplated that the size of the jacket146 could be increased in other ways to accommodate expansion of thecore. For example, releasable tucks could be formed in the jacket. Uponexpansion of the core, stitches or other devices holding the tucks wouldbe released under the influence of force applied against the jacket bythe core.

Anchor—Fifth Embodiment

The anchors illustrated in FIGS. 1-9 all have passages through which thesuture extends. In the embodiment of the invention illustrated in FIG.10, the anchor has an eyelet through which the suture extends. Since theembodiment of the invention illustrated in FIG. 10 is generally similarto the embodiment of the invention illustrated in FIGS. 1-9, similarnumerals will be utilized to designate similar components, the suffixletter “e” being associated with the embodiment of the inventionillustrated in FIG. 10 to avoid confusion.

An anchor 20 e has a solid cylindrical body portion 116 e. The bodyportion 116 e of the anchor 20 e is formed of a hydrophilic polymericmaterial which absorbs body liquid when exposed to the body liquid. Thematerial forming the body portion of the anchor 20 e is the same as thematerial forming the anchor 20 of FIGS. 1-4. Upon absorbing body liquid,a portion 116 e of the anchor 20 e expands.

In accordance with a feature of the embodiment of the inventionillustrated in FIG. 10, the anchor 20 e is provided with a trailing endportion 160 which is connected with a suture. The trailing end portion160 of the anchor 20 e has a circular wall 162 which is fixedlyconnected with the body portion 116 e of the anchor 20 e. A passage 30 eis formed in a projection 164 which extends axially outward from the endwall 162. The passage 30 e receives a suture. The suture may be tied offon the projection 164 or may extend through the projection and have apair of legs, corresponding to the legs 34 and 38 of the suture 32 ofFIG. 1.

When the anchor 20 e is inserted into body tissue, using an inserterassembly similar to the inserter assembly 60 of FIGS. 1 and 2, the bodyportion 116 e is exposed to body liquid. This results in the bodyportion 116 e of the anchor 20 e expanding radially and axially outwardfrom the trailing end portion 160 to form a mechanical interlock withthe body tissue.

Anchor—Sixth Embodiment

In the embodiments of the invention illustrated in FIGS. 1-10, at leastportions of the anchors are formed of a hydrophilic polymeric materialwhich absorbs body liquid. In the embodiment of the inventionillustrated in FIG. 11, the anchor is formed of cellular material whichabsorbs body liquid. Since the embodiment of the invention illustratedin FIG. 11 is generally similar to the embodiments of the inventionillustrated in FIGS. 1-10, similar numerals will be utilized todesignate similar components, the suffix letter “f” being associatedwith the numerals of FIG. 11 to avoid confusion.

A suture anchor 20 f has a tubular cylindrical configuration when theanchor is in an unrestrained condition. When the suture anchor 20 f isin an unrestrained condition, the anchor has a tubular wall 24 f whichhas a cylindrical outer side surface 26 f which is coaxial with acylindrical inner side surface 28 f of the anchor. The cylindrical innerside surface 28 f forms a passage 30 f which extends axially through thecenter of the suture anchor 20 f when the anchor is in an unrestrainedcondition.

The wall 24 f of the suture anchor 20 f is formed as one piece ofresilient material containing a large number of cells which areexpandable to absorb body liquid. The cellular material which forms thesuture anchor 20 f may be a hydrophilic polymeric cellular materialwhich absorbs body liquid. Although it is preferred to form the anchor20 f with a cylindrical configuration, the anchor may be shaped to anyone of many different axially tapering or flaring configurations or mayhave a polygonal configuration.

A suture 32 f is inserted into the passage 30 f in the suture anchor 20f. The suture 32 f includes a leg portion 34 f which extends away from aflat annular trailing end surface 36 f of the anchor 20 f. In addition,the suture 32 f has a second portion or leg 38 f which extends across aflat annular leading end surface 40 f of the anchor 20 f. The leg 38 fof the suture 32 f extends along the cylindrical outer side surface 26f. A relatively short portion 44 f of the suture 32 f interconnects theleg portion 34 f and 38 f and is disposed in the passage 30 f in theanchor 20 f.

An inserter assembly 60 f is used to position the anchor 20 f and aportion of the suture 32 f in a patient's body tissue 22 f. The inserterassembly 60 f includes a cylindrical tubular outer sleeve 66 f having acylindrical passage 68 f in which the anchor 20 f is disposed. Theinserter 60 f also includes a cylindrical tubular inner sleeve 72 fwhich is telescopically received in the outer sleeve 66 f. The tubularinner sleeve 72 f has a cylindrical leading end portion 74 f whichengages the trailing end surface 36 f of the anchor 20 f.

The leading end portion 74 f of the tubular inner sleeve 72 f has an endwall 168 with a flat end surface which abuttingly engages the flatannular trailing end surface 36 f on the anchor 20 f. The two legs 34 fand 36 f of the suture 32 f extend through a central opening formed inthe end wall 168 at the leading end portion 74 f of the inner sleeve 72f. The legs 34 f and 38 f of the suture 32 f extend through the tubularinner sleeve 72 f to a location remote from the inserter assembly 60 f.If desired, one of the legs 34 f or 38 f of the suture could be omitted.If this was done, the suture 32 f could be tied or otherwise secured tothe anchor 20 f.

It is contemplated that the anchor 20 f may be inserted into a humanpatient's body at many different locations. The anchor 20 f may beinserted into either hard or soft tissue. In the situation illustratedschematically in FIG. 11, the anchor 20 f is being inserted into softbody tissue in a patient's body.

To facilitate insertion of the anchor 20 f into soft body tissue, aleading end portion 170 of the outer sleeve 60 f has an axially taperedor configuration. The pointed configuration of the leading end portion170 of the outer sleeve 60 f enables the leading end portion of theouter sleeve to form an opening in an imperforate outer side surface 114f of the patient's body tissue 22 f. In addition, the pointed leadingend portion 170 of the outer sleeve 60 f facilitates moving the outersleeve 60 f into the body tissue 22 f under the influence of forcemanually applied against an outer end portion of the outer sleeve 60 f.

To insert the anchor 20 f into the patient's body tissue 22 f, thepointed leading end portion 170 of the outer sleeve 66 f is pressedagainst the imperforate outer side surface 114 f of skin or other tissue120 f. The pointed leading end portion of the outer sleeve 66 f piercesthe imperforate outer surface 114 f of the skin 120 f and enters softbody tissue 122 f disposed beneath the skin. The outer sleeve 66 f isforced into the soft body tissue 22 f for a desired distancecorresponding to the distance which the suture anchor 20 f is to beinserted into the body tissue.

The inner sleeve 72 f is then pressed downward (as viewed in FIG. 11) tomove the suture anchor 20 f to the leading end portion 170 of the outertubular member 66 f. The inner side surface 68 f of the tubular outermember 66 f applies force against the outer side surface 26 f of theanchor 20 f to maintain the anchor in the compressed condition shown inFIG. 11. The outer tubular member 66 f is then moved axially upward (asviewed in FIG. 11) relative to the stationary inner tubular member 72 f.This results in the anchor 20 f being ejected from the outer tubularmember 66 f into the body tissue 22 f. Once the anchor 20 f has movedfrom the outer sleeve 66 f into the body tissue 22 f, both the inner andouter sleeves 66 f and 72 f are withdrawn from the body tissue.

If desired, a pointed member, such as a trocar, could be insertedthrough the outer sleeve 66 f to pierce the surface 114 f and bodytissue 22 f. If this was done, the inner sleeve 72 f and anchor 20 fwould be removed from the outer sleeve 66 f to provide room for thepointed member. After the body tissue has been pierced by the pointedmember, the pointed member would be withdrawn from the outer sleeve 66 fand the inner sleeve 72 f and compressed anchor 20 f inserted into theouter sleeve.

In accordance with a feature of the present invention, the anchor 20 fis formed of a resilient cellular material. Prior to insertion of theanchor 20 f into the outer sleeve 66 f, the cellular material of theanchor 20 f is resiliently compressed from a relatively largeunrestrained size to a compacted size illustrated in FIG. 11. Theunrestrained size of the suture anchor 20 f may be 2 to 20 times aslarge as the size illustrated in FIG. 11.

As the resilient cellular material of the anchor 20 f is compressed, thepassage 30 f which extends through the anchor 20 f when the anchor is inits unrestrained condition, is collapsed tightly inward against theportion 44 f of the suture 32 f. In addition, as the anchor 20 f isresiliently compressed from its unrestrained condition, the cells in theanchor are collapsed. Thus, the anchor 20 f is resiliently compressedfrom an unrestrained condition to the compacted or compressed conditionof FIG. 11 in much the same manner as in which a sponge may becompressed.

The compressed anchor 20 f, with the suture 32 f extending through theanchor and the inner sleeve 72 f, is inserted into the outer sleeve 66f. The inner sleeve 72 f then pushes the compressed anchor axiallydownward (as viewed in FIG. 11) into the outer sleeve as the telescopicrelationship between the inner and outer sleeves is increased.

When the anchor 20 f is in the outer sleeve 66 f, the inner side surface68 f of the outer sleeve applies force against the outer side surface 26f of the anchor to hold the anchor in its compressed condition. Uponmovement of the anchor 20 f out of the outer sleeve 66 f into the bodytissue 22 f, the force holding the anchor 20 f in a compressed conditionis removed from the outer side surface 26 f of the anchor. As thisoccurs, the natural resilience of the cellular material forming theanchor 20 f causes the anchor to expand.

As the anchor 20 f expands, the anchor applies force against the softbody tissue 122 f and increases the size of the cavity which wasoriginally formed by the outer sleeve 66 f of the inserter assembly 60f. As the anchor 20 f expands, it applies force against the soft bodytissue 122 f and displaces the soft body tissue. Thus, the outer sidesurface 26 f of the anchor 20 f is pressed against the soft body tissue122 f and moves the soft body tissue as the anchor expands radiallyoutward.

As the anchor 20 f expands, the cells in the anchor are expanded from acollapsed condition to an expanded condition. As the size of the cellsin the anchor 20 f increases, body liquids are drawn into the cells.Thus, the anchor 20 f absorbs body liquid as it expands.

The anchor 20 f is formed of a resilient polymeric material having anopen cell, sponge-like construction. When the anchor 20 f is in thecompressed condition illustrated in FIG. 11, the cells are collapsed. Asthe anchor 20 f expands in the body tissue 22 f, the cells expand. Sincethe anchor 20 f has an open cellular construction, body liquid can flowinto the cells as the anchor expands.

Once the anchor 20 f has expanded in the body tissue 22 f, the expandedanchor is substantially larger than the opening which was formed in thebody tissue by insertion of the outer sleeve 66 f into the body tissue.However, it should be understood that due to force applied against theanchor 20 f by the body tissue 22 f, the anchor may not expand fullyback to its unrestrained size. As the outer sleeve 66 f is withdrawnfrom the body tissue, the visco-elastic nature of the body tissue causesthe body tissue to come together and close off the passage which wasformed by the insertion of the outer sleeve 66 f into the body tissue.Thus, the body tissue will move inward and grip the legs or portions 34f and 38 f of the suture 32 f. The anchor 20 f will fill a cavity formedin the body tissue 22 f by expansion of the anchor.

The expansion of the anchor 20 f in the body tissue results in theformation of an interlock between the anchor and the body tissue toprevent the anchor from being pulled out of the body tissue under theinfluence of tension applied to the suture 32 f. The suture 32 f may beused to position a member which is body tissue, in the manner similar tothat illustrated in FIGS. 3 and 4, or may be used to position a splintor implant member relative to the body tissue. Since the expanded anchor20 f has a firm interlock with the body tissue 122 f, tension forcestransmitted through the suture 32 f between the anchor 20 f and a memberheld in place by the suture will not pull the anchor 20 f out of thebody tissue.

In FIG. 11, the compressed suture anchor 20 f is being inserted into asolid mass of soft body tissue 122 f. However, it is contemplated thatthe suture anchor 20 f could be inserted into either a natural orartificial body cavity. If this was done the suture anchor 20 f wouldexpand to at least partially fill the body cavity.

Alternative Anchor Insertion Apparatus

In the embodiment of the invention illustrated in FIG. 11, the anchor 20f moves through the open end portion 170 of the outer sleeve 66 f intothe body tissue 22 f. In the embodiment of the invention illustrated inFIG. 12, the outer sleeve has a closed pointed end portion and theanchor is moved from the outer sleeve at a location immediately behindthe pointed end portion of the outer sleeve. Since the embodiment of theinvention illustrated in FIG. 12 is generally similar to the embodimentof the invention illustrated in FIG. 11, similar numerals will beutilized to designate similar components, the suffix letter “g” beingassociated with the numerals of FIG. 12 to avoid confusion.

An anchor 20 g has the same construction and is formed of the sameresilient open cell material as the anchor 20 f of FIG. 11. A suture 32g has a leg or portion 34 g which extends from a flat annular trailingend surface 36 g of the cylindrical anchor 20 g. A second leg or portion38 g of the suture 32 g extends from a flat annular leading end surface40 g of the anchor 20 g. A portion 44 g of the suture 32 g extendsthrough the anchor and interconnects the legs or portions 34 g and 38 g.

The two legs or portions 34 g and 38 g of the suture 32 g extend througha cylindrical central passage in an outer sleeve 72 g of an inserterassembly 60 g. The inner sleeve 72 g is disposed in a telescopicrelationship with a cylindrical outer sleeve 66 g of the inserterassembly 60 g. The inner sleeve 72 g cooperates with the outer sleeve 66g in the same manner as previously explained in conjunction with theinserter assembly of FIG. 11.

In accordance with a feature of this embodiment of the invention, theouter sleeve 66 g has a solid pointed end portion 170 g with a generallyconical configuration. The pointed end portion 170 g is utilized topierce an imperforate surface of body tissue in much the same manner asin which the end portion 170 of the outer sleeve 66 f of the inserterassembly 60 f (FIG. 11) is used to pierce an imperforate surface 114 fof the body tissue 22 f.

In accordance with one of the features of the present invention, theouter sleeve 66 g has a generally oval opening 180 in a cylindricalouter side surface 182 of the outer sleeve 66 g. The opening 180 isconnected with a central passage 68 g. The passage 68 g extends from anopen upper (as viewed in FIG. 12) end portion of the outer sleeve 66 gto the solid pointed leading end portion 170 g.

When the outer sleeve 66 g has been inserted to the desired depth inbody tissue, the inner sleeve 72 g is moved axially downward (as viewedin FIG. 12) and the anchor 20 g is forced along an arcuate cam surface184 leading to the opening 180. This results in the anchor 20 g beingforced from the passage 68 g in the outer sleeve 66 g into the soft bodytissue. As this occurs, the leading end 40 g of the anchor 20 g appliesforce against the body tissue to displace the body tissue and providespace for the anchor.

As the anchor 20 g moves along the passage 68 g and through the opening180, the orientation of the anchor relative to the body tissue changes.Thus, the orientation of the anchor 20 g changes from the orientationshown in FIG. 12 to an orientation similar to the orientation of theanchor 20 in FIG. 3. This pivotal movement of the anchor 20 g results inthe anchor moving from an initial orientation in which a central axis ofthe anchor extends parallel to and is coincident with a central axis ofthe outer sleeve 66 g to an orientation in which the central axis of theanchor 20 g extends perpendicular to the central axis of the outersleeve 66 g.

As the anchor 20 g exits from the passage 68 g in the outer sleeve 66 g,the anchor 20 g expands under the influence of its own naturalresilience and further displaces body tissue. Once the inner sleeve 72 ghas been moved downward to the maximum extent possible, that is, to aposition in which the leading end of the inner sleeve 72 g engages thecam surface 184, the inner and outer sleeves are withdrawn together fromthe body tissue. As this occurs, engagement of the anchor 20 g with thebody tissue causes the trailing end portion of the anchor to move out ofthe passage 68 g in the outer sleeve 66 g.

As the outer sleeve 66 g continues to be withdrawn, the pointed leadingportion 170 of the outer sleeve moves upward (as viewed in FIG. 12),past the anchor 20 g. As this occurs, the anchor 20 g expands into thespace previously occupied by the leading end portion 170 g of the outersleeve 66 g. As the outer sleeve 66 g and inner sleeve 72 g arewithdrawn from the body tissue, the visco-elastic body tissue closesaround the anchor 20 g and the legs 34 g and 38 g of the suture 32 g.

As the anchor 20 g is forced from the outer sleeve 66 g into the bodytissue and expands, cells in the anchor 20 g also expand. As the cellsin the anchor 20 g expand, body liquid is drawn into and at leastpartially fills the cells in the anchor. The anchor 20 g has an opencellular construction, similar to the construction of a sponge. Theanchor 20 g is resiliently compressed prior to insertion into the outersleeve 66 g so that the cells in the anchor 20 g are resilientlycollapsed until the anchor is allowed to expand as it is forced out ofthe side opening 180 in the outer sleeve 66 g.

Changing Configuration of Anchor

In the embodiment of the invention illustrated in FIGS. 1-3, the generalconfiguration of the anchor 20 is illustrated as being maintainedconstant. Thus, the anchor 20 has a cylindrical tubular configurationwith a linear central axis. In the embodiment of the inventionillustrated in FIG. 13, the configuration of the anchor is changed whilethe anchor is in a patient's body tissue. Since the embodiment of theinvention illustrated in FIG. 13 is generally similar to the embodimentof the invention illustrated in FIGS. 1-4, similar numerals will beutilized to designate similar components, the suffix letter “h” beingassociated with the numerals of FIG. 13 to avoid confusion.

A suture anchor 20 h has the same construction and is formed of the samehydrophilic polymeric material as the suture anchor 20 of FIGS. 1-3. Thesuture anchor 20 h (FIG. 13) has a cylindrical tubular configuration.The suture anchor 20 h has a cylindrical outer side surface 26 h. Acylindrical central passage (not shown) extends through the sutureanchor 20 h between opposite annular end surfaces 36 h and 40 h of thesuture anchor 20 h.

A suture 32 h has a leg 34 h which extends from an annular end surface36 h of the anchor 20 h. A second leg 38 h of the suture 32 h extendsfrom the opposite end surface 40 h of the anchor 20 h. The anchor 20 his inserted into body tissue 20 h in the same manner as in which theanchor 20 f of FIG. 11 is inserted into the body tissue 22 f. Thus, aninserter assembly, similar to the inserter assembly 60 f of FIG. 11, isused to position the anchor 20 h in the body tissue 22 h. The inserterassembly may include a tubular outer sleeve, corresponding to the sleeve66 f of FIG. 11 and a tubular inner sleeve, corresponding to the innersleeve 72 f of FIG. 11. However, the inner sleeve 72 f is provided witha conical leading end portion having a configuration corresponding tothe configuration of the leading end portion 74 (FIG. 1) of the innersleeve 72. This enables the inserter assembly to pivot the suture anchor20 h to the position shown in FIG. 13.

The outer sleeve of the inserter assembly which is used to position theanchor 20 h in the body tissue 22 h has a pointed leading end portion,corresponding to the pointed leading end 170 of the outer sleeve 66 f ofthe inserter assembly 60 f of FIG. 11. The pointed leading end of theouter sleeve of the inserter assembly was used to pierce the imperforateouter side surface 114 h of skin 120 h and to enter soft body tissue 122h.

As the anchor 20 h was positioned in the soft body tissue 122 h, theopposite legs 34 h and 38 h of the suture 32 h were tensioned. Thisresulted in the suture 32 h applying force against the opposite flatannular end surfaces 36 h and 40 h of the anchor 20 h. The force appliedto opposite ends of the anchor 20 h by the suture 32 h pulled the outerside surface 26 h of the anchor against the body tissue 122 h. Inaddition, the force applied against opposite ends of the anchor 20 h bythe suture 32 h caused the suture to bend from an initial configurationto the deflected configuration shown in FIG. 13.

When the anchor 20 h was in the initial configuration, the anchor 20 hhad a straight longitudinal central axis, the same as the anchor 20 ofFIGS. 1-3. However, tensioning the suture 32 h caused the legs 34 h and38 h of the suture to apply force against opposite ends of the anchor 20h and pull the anchor against the body tissue 122 h. As this occurred,the anchor was deflected to the arcuate configuration illustrated inFIG. 13. Since the anchor 20 h is formed of the same hydrophilicpolymeric material as the anchor 20 of FIGS. 1-3, the anchor 20 habsorbs body fluid and expands in the body tissue 122 h while the anchorhas the deflected configuration illustrated in FIG. 13.

Deflection of Anchor—Second Embodiment

In the embodiment of the invention illustrated in FIG. 13, theconfiguration of the anchor 20 h is changed from an initialconfiguration in which the anchor has a straight longitudinal centralaxis to a configuration in which the anchor has an arcuate longitudinalcentral axis by tensioning the suture 32 h to apply force againstopposite ends of the anchor. In the embodiment of the inventionillustrated in FIG. 14, the configuration of the anchor is changed froman initial configuration to a deflected configuration by tensioning asuture which is connected with a central portion of the anchor. Sincethe embodiment of the invention illustrated in FIG. 14 is generallysimilar to the embodiment of the invention illustrated in FIG. 13,similar numerals will be utilized to designate similar components, thesuffix letter “j” being associated with the numerals of FIG. 14 to avoidconfusion.

An anchor 20 j has an outer side surface 26 j. The outer side surface 26j extends between opposite end surfaces 36 j and 40 j of the anchor.

A suture 32 j is connected with a central portion of the anchor 20 jdisposed between the opposite end surfaces 36 j and 40 j. The anchor 20j is formed of the same hydrophilic polymeric material as the anchor 20of FIGS. 1-3. The anchor 20 j is inserted into body tissue 22 j in thesame manner as described in connection with the embodiment of theinvention illustrated FIG. 13.

Prior to insertion of the anchor 20 j into the body tissue 22 j, theanchor 20 j has a solid cylindrical configuration with a straightlongitudinal central axis. As the anchor 20 j is inserted into the bodytissue 22 j and moved to the orientation shown in FIG. 14, the suture 32j is tensioned. Tensioning of the suture 32 j presses the outer sidesurface 26 j of the anchor 20 j against the body tissue 22 j. As thisoccurs, the anchor 20 j is deflected from its initial configuration tothe deflected configuration illustrated in FIG. 14. When the anchor 20 jis in the deflected orientation, the longitudinal central axis of theanchor has an arcuate configuration.

1. A method of securing a suture comprising: providing a suture anchorhaving a generally tubular configuration and a passage extending axiallytherethrough; positioning a portion of a suture within the passage ofthe anchor; inserting the anchor into body tissue with the sutureextending from the anchor; expanding a portion of the suture anchorradially outward to lock the anchor within the body tissue; andtensioning the suture.
 2. The method of claim 1, further includingcreating a recess in the body tissue and wherein inserting the anchorincludes inserting the anchor within the recess.
 3. The method of claim2, wherein the body tissue is bone.
 4. The method of claim 3, whereinthe recess is created by drilling the bone.
 5. The method of claim 4,wherein the anchor has an initial orientation during the insertion stepand maintains the initial orientation during the expansion step.
 6. Themethod of claim 5, further including the step of securing soft tissuerelative to the bone.
 7. The method of claim 1, wherein the sutureanchor has first and second configurations, the anchor having the firstconfiguration prior to expansion and the second configuration afterexpansion.
 8. The method of claim 7, wherein the first configuration ofthe anchor is smaller in diameter than the second configuration.
 9. Themethod of claim 8, wherein the second configuration of the suture anchorlocks the anchor into the body tissue.
 10. The method of claim 1,wherein expanding the anchor includes increasing a cross sectional areaof the anchor as viewed in a plane extending perpendicular to thelongitudinal axis of the anchor.
 11. The method of claim 10, wherein theincreased cross sectional area of the suture anchor locks the anchorinto the body tissue.
 12. The method of claim 1, wherein the anchor ismade of a polymeric material.
 13. The method of claim 1, wherein theanchor includes both polymeric and ceramic materials.
 14. The method ofclaim 13, wherein the polymeric material is a resorbable polymer.
 15. Amethod of securing a suture comprising: providing a suture anchor havinga generally tubular configuration and a passage extending axiallytherethrough; positioning a portion of a suture within the passage ofthe anchor; creating a recess in bone; inserting the anchor into therecess with the suture extending from the anchor; increasing an crosssectional diameter of a portion of the suture anchor to lock the anchorwithin the bone; and tensioning the suture.
 16. The method of claim 15,wherein the recess has a substantially cylindrical shape.
 17. The methodof claim 16, wherein the anchor has an initial orientation during theinsertion step and maintains the initial orientation thereafter.
 18. Themethod of claim 17, further including the step of securing soft tissuerelative to the bone with the suture.